Metal & Plastic Finishing: Dewax, Strip & Deplate
Finish treatment on metal and plastic first identifies the soil (wax/oil/paint/plating), then chooses alkaline, acidic or solvent routes — substrate tolerance is the floor.
1Identify the soil first
Buffing wax, stamping oil and cutting fluid are oily and need emulsification or saponification; paint/ink are polymers needing solvent penetration or strong-alkali swelling; plating (Cr/Ni/Cu/Zn) needs oxidation + complexation or a dedicated deplate. Confirm single vs composite soil, and use multi-component synergy for mixed soils.
2Three routes
Dewax: alkaline saponification plus hot/ultrasonic emulsification; paint strip: strong alkali or solvent (limited halogenated types; eco grades use alkali plus additives); deplate: traditional cyanide is restricted in favor of non-cyanide oxidation + complexation (mild systems for Mo/Ti). Spray lines need low-foam grades.
3Substrate & safety
Al/Mg alloys corrode and darken above pH 9, so use neutral or mild alkali with inhibitors; copper alloys are sensitive to strong acid oxidizers; plastics vary in solvent resistance (PC resists ketones/halogenated, ABS resists some solvents) — do a compatibility test first. Strong alkali/acid needs PPE and temperature control.